Power supply



FIG. 1 is top view thereof;

FIG. 2 is a bottom view thereof;

FIG. 3 is a right-side view thereof;

FIG. 4 is a left-side view thereof;

FIG. 5 is a front view thereof; and,

FIG. 6 is a back view thereof. 

The ornamental design for a power supply, substantially as shown. 